Coring apparatus



March 22, 1966 J. D. MARTINEZ GORING APPARATUS Filed Sept. 18, 1965FIG.IA.

INVENTOR.

JOSEPH D- MARTINEZ,

ATTORNEY.

United States Patent 3,241,623 CORING APPARATUS Joseph D. Martinez, DeKalb, Ill., assignor, by mesne assignments, to Esso Production ResearchCompany, Houston, Tex., a corporation of Delaware Filed Sept. 18, 1963,Ser. No. 309,822 5 Claims. (Cl. 175-44) This invention relates to thetaking of a subsurface core and the orienting of the subsurface core.More particularly, this invention is a novel apparatus for obtaining anoriented subsurface core.

During the drilling of a borehole in the search for oil or otherminerals, core samples are cut from the formations being traversed andare removed to the earths surface for examination. Various, importantinformation can be obtained from such a core. For example, if anybedding planes are observable in the core, the strike and dip of theseplanes (and hence of the formation from which the core was obtained) canbe determined. The true directions of strike and dip, however, can bedetermined only if the core can be oriented (in space) in the same Waythat it was oriented in its original place in the formation.

There are several methods now in use which are satisfactory fororienting a core if the core is preserved intact. If, however, the coreis broken into segments, as is frequently the case, and the segmentscannot be fitted together, then only the orientation of the topmostsegment will be preserved. The apparatus to be described hereinpreserves the orientation of the entire core even if it is broken intosegments.

Briefly described, my new apparatus for cutting a core from the bottomof a borehole comprises a first tubular member having a cylindricalcavity formed therein. A second tubular member is positioned within thecavity formed in the first tubular member. The bores of the two tubularmembers have approximately the same diameter. The first tubular memberis rotated about the second tubular member during the cutting of a core.A scratcher extends from the second tubular member into the borethereof.

The scratcher is maintained in continuous contact with the side of thecore as the core is being cut. The result is that a mark on the core isprovided and can be traced from top to bottom when the segments of thecore are fitted together.

The invention, as well as its many advantages, may be further understoodby reference to the following detailed description and drawings inwhich:

FIGS. 1 and 1A are longitudinal, sectional views showing the generalarrangement of my new apparatus; and

FIG. 2 is a view taken along line 2-2 of FIG. 1.

Referring to the drawings and more particularly to FIG. 1, numeralrefers to a sub on the lower section of a drill string which is loweredinto the borehole. Threadedly connected to the sub 10 of the drillstring is an outer core barrel 12. Threadedly connected to the outercore barrel 12 is a core bit 14 used in drilling the core 16. As thecore bit 14 is rotated, the core 16 is forced upwardly through a corecatcher 18 which is attached to the lower extremity of an inner barrel20. The upper portion of the inner barrel 20 is connected to a rod 22.The rod 22 extends to the lower portion of the drill string sub 10.Connected to the lower portion of the drill string sub 10 and forming anintegral part thereof is a. sleeve member 24. It can be seen from anexamination of FIG. 1 that the sub 10, the outer core barrel 12, and thesleeve member 24 rotate with the core bit 14 when the drill string isrotated to cut the core 16. The rod 22 to which the inner barrel 20 isattached remains stationary ice as the core 16 is forced into the innerbarrel 20. Suitable bearings 26 are positioned between the rod 22 andthe sleeve member 24 to provide for the rotation of the rotating membersabout the stationary members. To prevent any of the circulating fluidsfrom getting into the bearings 26, suitable packing means 28 and 29 areprovided.

The usual core-orienting means shown in dotted lines are provided in theupper chamber of sub 10' to properly orient the core within theborehole.

Referring to FIGS. 1 and 2, it can be seen that the outer core barrel 12contains a substantially cylindrical cavity 30. The substantiallycylindrical cavity 30 is formed by providing a series of an upper step32 and lower step 34, upper step 36 and lower step 38, and upper step 49and lower step 42. The cavity 30 thus decreases in height as it extendsfrom the bore 44.

A tubular member 46 having a bore 48 of substantially the same diameteras the bore 44 in outer core barrel 12 is mounted within the cavity 30.The tubular member 46 is provided with an upper shoulder 50 and a lowershoulder 52.

A chamber 54 is formed in the tubular member 46. The chamber 54 extendsfrom the bore 48 to a point within the tubular member 46. A scratcher 56having a point 58 is mounted Within the chamber 54. The point 58 ofscratcher 56 extends into the bore 48 because of the bias of coil spring60. An upper circular race 62 and a lower circular race 64 are mountedon the steps 36 and 38, respectively, within outer core barrel 12. Anupper circular race 66 and a lower circular race 68 are mounted on theshoulders 50 and 52, respectively, of tubular member 46. Races 62 and 66provide a raceway for a plurality of ball bearings 70. Races 64 and 68provide a raceway for a plurality of ball bearings 7.2.

A circular groove 74 and a circular groove 76 are formed in the innersurface 78 and outer surface 80, respectively, of outer core barrel 12and tubular member 46, respectively, to form a bearing raceway. Aplurality of roller bearings 82 is circularly mounted within the grooves74 and 76.

In operation, as the core 16 is being cut, the outer core barrel 12rotates about the tubular member 46. As the core 16 is cut, the point 58of scratcher 56 forms a mark 84 in the core 16 extending from the top ofcore 16 vertically downward. The tubular member 46 is prevented fromrotating appreciably by the scratcher. Hence, even if the core 16 shouldbreak into segments as it is removed at the surface of the earth, themark 84 on core 16 can be used to fit the segments together. Thus, theorientation of all the segments of the core is preserved.

I claim:

1. In an apparatus for cutting a core from the bottom of an earth bore:a first tubular member having a substantially cylindrical cavity formedtherein; a second tubular member positioned in said cavity and havingsubstantially the same inside diameter as the first tubular member;means adapted to permit the rotation of the first tubular member aboutthe second tubular member during the cutting of a core; and a singlescratcher extending from the second tubular member into the borethereof.

2. An apparatus in accordance with claim 1 wherein said second tubularmember has a chamber formed there in from its inside perimeter, biasingmeans is mounted in the chamber, and the scratcher is biased into thebore of the second tubular member by the biasing means.

3. An apparatus in accordance with claim 1 wherein the means adapted topermit the rotation of the first tubular member about the second tubularmember during the cutting of a core includes a plurality of rollerscircularly mounted within the substantially cylindrical cavity.

4. An apparatus in accordance with claim 1 wherein the means adapted topermit the rotation of the first tubular member about the second tubularmember during the cutting of a core includes: an upper circular race anda lower circular race mounted in the substantially cylindrical cavity;an upper circular race and a lower circular race mounted on the secondtubular member, the upper circular race being mounted directly below andthe lower circular race being mounted directly above the upper and lowercircular races, respectively, mounted in the substantially cylindricalcavity to provide an upper raceway and a lower raceway; and a pluralityof ball bearings mounted in each of said raceways.

5. In an apparatus for cutting a core from the bottom of an earth bore:a first tubular member having a substantially cylindrical cavity formedtherein; a second tubular member positioned in said cavity and havingsubstantially the same inside diameter as the first tubular member; aplurality of rollers circularly mounted within the substantiallycylindrical cavity; an upper circular race and a lower circular racemounted in the substantially cylindrical cavity; an upper circular raceand a lower circular race mounted on the second tubular member, theupper circular race being mounted directly below and the lower circularrace being mounted directly above the upper and lower circular races,respectively, mounted in the substantially cylindrical cavity to providean upper raceway and a lower raceway; and a plurality of ball bearingsmounted in each of said raceways; a chamber formed in the second tubularmember; a single scratcher mounted in the chamber; and biasing meansalso mounted in the chamber adapted to bias the single scratcher intothe bore of the second tubular member.

References Cited by the Examiner UNITED STATES PATENTS 1,701,724 2/1929McLaughlin 17544 2,580,510 1/1952 Brady 175-44 2,657,013 10/1953 Brady175-44 CHARLES E. OCONNELL, Primary Examiner,

R. E. FAVREAU, Assistant Examiner.

1. IN AN APPARATUS FOR CUTTING A CORE FROM THE BOTTOM OF AN EARTH BORE:A FIRST TUBULAR MEMBER HAVING A SUBSTANTIALLY CYLINDRICAL CAVITY FORMEDTHEREIN; A SECOND TUBULAR MEMBER POSITIONED IN SAID CAVITY AND HAVINGSUBSTANTIALLY THE SAME INSIDE DIAMETER AS THE FIRST TUBULAR MEMBER;MEANS ADAPTED TO PERMIT THE ROTATION OF THE FIRST TUBULAR